The Effects Of Regulating Arterial Blood Carbon Dioxide Tension On The Hemodynamic Changes During Laparoscopic Cholecystectomy

Background Laparoscopic surgery is a common surgical procedure.Carbon dioxide （CO₂） insufflation is associated with persistent increasesin the heart rate and blood pressure until desufflation, increasing plasmavasopressin and catecholamine concentration. These changes are relatedto increases in arterial carbon dioxide tension by30%above the normallevels. Extra CO₂can be cleared by adequate ventilation with enoughpulmonary perfusion. The rise in CO₂could be compensated byhyperventilation of the lungs with a30%increase in minute ventilation.Relative low PaCO₂after anesthesia induction throughout CO₂insufflation may reduce the blood pressure increases in response to CO₂insufflation with less doses of anesthetic agents. Objective to comparethe effects of regulating different arterial blood carbon dioxide tension onhemodynamics of patients undergoing laparoscopic cholecystectomy.Methods60ASA I/II patients receiving elective laparoscopiccholecystectomy in the first hospital of Jilin university were allocatedrandomly to group A （30-35mmHg of PaCO₂）or group B（45-50mmHg ofPaCO₂）. The same anesthesia was carried out. Propofol and remifentanilwere injected intravenously to maintain anesthesia. Minute ventilationwas adjusted by altering the RR to achieve a PaCO₂of30to35mmHg in group A and a PaCO₂of45to50mmHg in group B. Record and comparethe variables inchuding SBP, MBP, PaCO₂, PetCO₂, Pa-etCO₂, RR, Paw，PaO₂,PH and doses of remifentanil and propofol, emergency time andtime to extubation. Results Compared with group B, group A wasassociated with significantly lower arterial blood pressures, lower PaCO₂and EtCO₂values, less doses of remifentanil and propofol, and a higherPa-etCO₂, a higher RR （p＜0.05）. There was no significant differenceassociated with PaO₂, PIP and emergence time and time to extubation.In both of the two groups,the arterial blood PH was between7.30-7.45.no alkalosis occurred. Conclusion we conclude that lowPaCO₂before and during CO₂insufflation by ventilation is effective inattenuating increases in blood pressure after CO₂pneumoperitoneumduring anesthesia for laparoscopic cholecystectomy,without effects onacid-base equilibrium and recovery from anesthesia.